Dental plaque is present to some degree in the form of a film on dental surfaces. It is a byproduct of microbial growth, and comprises a dense microbial layer consisting of a mass of microorganisms embedded in a polysaccharide matrix. It is reported that plaque adheres firmly to dental surfaces and is removed only with difficulty even through a rigorous brushing regimen. Moreover, plaque rapidly re-forms on the tooth surface after it is removed. Plaque may form on any part of the tooth surface, and is found particularly at the gingival margin, in cracks in the enamel, and on the surface of dental calculus. The problem associated with the formation of plaque on the teeth lies in the tendency of plaque to build up and eventually produce gingivitis, periodontitis and other types of periodontal disease, as well as dental caries, bad breath (halitosis) and dental calculus.
As plaque is formed by oral bacteria, a wide variety of antibacterial agents have been proposed to retard plaque formation and the oral infections associated with plaque formation. For example, halogenated hydroxydiphenyl ether compounds such as triclosan are well known to the art for their antibacterial activity and have been used in oral compositions to counter plaque formation by bacterial accumulation in the oral cavity.
Xylitol is also well known to inhibit the growth of Streptocococcus mutans an oral bacteria implicated in plaque formation, and that this inhibition causes reduced acid formation which in turn is believed to inhibit caries formation. In the case of xylitol, because of its high water solubility the compound is quickly removed from the oral site, thus having a limited inhibitory effect upon reduced acid formation from S. mutans. 
These antibacterial agents which work to reduce plaque formation by temporary reduction in the population of oral bacteria have numerous disadvantages when incorporated into commercial products, including disadvantages stemming from regulatory frameworks of various jurisdictions, compatibility with mouth rinse formulation, staining effects on tooth surface, and substantivity to oral surfaces.
Accordingly, there remains a need in the art for new oral compositions that reduce or prevent plaque formation whilst overcoming the above disadvantages.